The present invention relates to apparatus for the demand cutting of rod or strandlike products, moved individually along a path of motion at a predetermined speed. The apparatus includes a plurality of cutting blades fixed to a rotating holder which is itself arranged adjacent the path of motion. The rotational axis of that blade holder is inclined relative to the longitudinal extension of the path of motion. The cutting blades are movable between cutting and non-cutting positions so that cutting will occur only when required or demanded. Also, the cutting blades are positioned so that the cutting edges of the blades are designed to pass through the products at right angles to the longitudinal extension of the path of motion during the cutting process.
There exist known apparatuses which are used for cutting cigarette rods into individual cigarettes. The feed movement of the cigarette rod and the rotary speed of the cutting blades are adapted to one another in such a way that precisely identically long pieces are always cut from the cigarette rod. The slope of the rotation axis of the support with respect to the longitudinal extension of the path of motion, i.e. with respect to the feed direction of the cigarette rod is selected in such a way that on passing through the path of motion and on separating the cigarette rod, the blades move at the same speed as the rod in the feed direction, i.e. cutting takes place without any acceleration or deceleration of the cigarette rod, but the cutting edges of the blades pass precisely perpendicularly through the rod.
Although such an apparatus is eminently suitable for the continuous cutting through of rod or strand-like articles, it cannot be used if only particular unusable areas are to be cut out or unusable ends cut off from rod or strand-like products. For example, this would be necessary when processing potato sticks, peeled comfrey, peeled carrots, etc., in which unsatisfactory parts, indicated by different coloring, have to be cut away while leaving the satisfactory parts.
For the processing of such products, an apparatus is already known in which the products, e.g. potato chips, are forced through a tube in a water stream flowing at known speed. The tube is transparent or translucent in at least one area, so that corresponding optical scanning arrangements can detect in said area, the presence of points having a differing coloring. By means of a compressed air jet flowing in the transverse direction, a sorting out force is produced at the end of the tube and those elongated articles are removed from the stream of articles which have been found to have a point with a differing coloring.
This known apparatus fulfills the demands made on it with a high output level, but has the disadvantage that it separates the complete article from the conveying area, although only a single, relatively small discolored point is found thereon. It is, therefore, necessary to again process the sorted out articles at a later time, i.e. to cut away or out the discolored points, so that then the remaining parts of the articles can be returned to the previously unsorted articles, or can be used for an inferior purpose.
An apparatus is also already known (DE-OS No. 2,630,930--U.S. Pat. No. 4,114,448) enabling the discolored points on elongated articles, e.g. potato sticks individually moved along a feed trough to be cut out or away and removed with the aid of a double cutting blade having spaced cutting edges in the feed direction, while the remaining part or parts of the article continues to be moved along the feed trough. Thus, by means of this known apparatus, it is possible to remove discolored points from articles, without the articles having such points being removed from the stream of the remaining and completely satisfactory articles and being supplied to a separate working process.
Although this known apparatus relatively reliably and satisfactorily removes the discolored points, it does not permit the processing of larger quantities of elongated articles per time unit in a feed trough. Therefore, the problem was to provide an apparatus for cutting off or out various areas from rod or strand-like articles, while permitting a high throughput of the latter.
According to the present invention, this problem is solved by apparatus where the cutting blades are movable between a working position, in which the cutting edge passes through the products, and a rest position in which the particular cutting blade is outside the range of the path of motion.
Thus, the apparatus according to this invention has blades continuously moving at the desired speed available for the cutting process and when an area to be removed is detected, one or more of the blades is moved from the rest or inoperative position into the working position, so that the blade or blades brought into the working position, which continuing their rotational movement, pass through the product and cut out an area therefrom.
The relatively short pieces that are cut out or off the main product continue to move with that product, but can subsequently be removed from the stream of objects due to their dimensions, e.g. by screening or sieving procedures.
According to a further development of the invention, the blades are fixed in the holder so as to be pivotable about a pivot axis and when the holder rotates, are preferably held in the inoperative or working position by centrifugal force. The pivot axis can be formed by a ball, pressed along a bore, which slopes radially outwards with respect to the rotation axis of the support, into the radially outwardly open blade reception slot within which the blade is positioned and moves.
In such an apparatus the blades, rotating continuously with the support, merely have to be pivoted to pass from the inoperative position into the working position and back again, while the cutting energy is supplied by the rotating support. The formation of the axis by a ball permits a very simple and compact construction, so that it is e.g. possible to place a very large number of blades with a limited spacing on the circumference of a circular support.
To prevent damage to the blades located in the working position, as a result of an excessively high feed or conveying speed of the products, the cutting edge of the blade in the inoperative position can be located in the direction of movement of the products behind the pivot axis of the blade, so that in the case of such an excessive speed, the products pivot the blade out of the working position in the direction of the inoperative position.
The pivoting of the blade from the inoperative position into the working position can take place, e.g. by means of a fluid jet, such as a gas jet. In this case, each blade extends on either side of its axis and the blade side opposite the side having the cutting edge is provided with an impact surface. Adjacent the support and in the direction of the rotation path of the blade, it is possible to provide a nozzle spaced from the path of motion for the articles or products. From such nozzle, a fluid jet is passed in a controlled manner onto the impact or deflection surface of the particular blade and as a result the latter is pivoted into its working position. The impact surface is preferably at right angles at the rotation axis of the support, so that an optimum pivoting action is caused by the fluid jet directed parallel to the longitudinal axis of the support.
In order to move the blade or blades from the working position back into the inoperative position, a return or resetting nozzle can be provided adjacent the support and in the direction of the rotation path of the blades and spaced from the path of motion of the articles or products. The return nozzle also supplies a fluid jet which pivots the particular blade back into the inoperative position, i.e. the return or resetting of the blade can take place in the same way as described herein before in connection with the pivoting of the blade into the working position.
Moreover, instead of the blades being pivotable, they can be constructed so as to move radially with respect to the rotational axis of the support between the working position and the in operative position. In this case, the blades can, for example, be held in the inoperative position by an electromagnet provided on the support and associated within each case one blade. This electromagnet can comprise a coil fixed on or in the support and a ferromagnetic material armature fixed to the blade.
For the return of the blade from the working position, it is possible to provide a cam in the rotation direction of the support and behind the path of motion, which cam constantly varies its spacing from the rotation axis of the support thereby returning the blades to their inoperative position as the cam spacing changes. The cam is positioned so that it engages blades located in the working position. As a result of the configuration of the cam or curve, the blades engaging therewith are consequently returned to their inoperative position.
The cam can be formed by a ring-shaped member positioned eccentrically relative to the support and which moves at essentially the same circumferential speed as the support. Thus, the engagement for the return of the blades takes place by means of part of the ring-shaped member, which is scarcely circumferentially displaced with respect to the blade, i.e. only causes limited abrasive wear.
It has been found that the support can be positioned close to the outlet end of a tube from which passes the water jet in which the products are entrained. Thus, it is this liquid jet that forms the path of motion through which the cutting blades can pass when needed. Accordingly, the products are in fact cut while entrained in the water jet, without impairing its feed movement or the feed movement of the products.
Other objects, features, and characteristics of the present invention as well as the methods and operation and functions of the related elements of the structure, and to the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures.